What are amino acids known as in relation to proteins?

Amino acids are known as the building blocks of proteins because they are the fundamental units that combine in various sequences to form proteins. Proteins themselves are essential macromolecules that play critical roles in the body, including structural functions, enzyme activities, and as components of hormones and antibodies. The unique sequence and combination of different amino acids determine the specific structure and function of each protein.

This understanding is key in nutrition and biology, as amino acids come together through peptide bonds to create polypeptides, which then fold into distinct shapes to become functional proteins. Each protein's specific function is highly dependent on the properties and arrangements of the amino acids it contains. In contrast, the other options do not accurately describe the role of amino acids in relation to proteins.